1. Field of the Invention
The present invention relates to a gene construct which is capable of achieving efficient production of an antimicrobial peptide in a microorganism, and a method for efficient mass production and separation of an antimicrobial peptide using the same.
2. Description of the Related Art
Antimicrobial peptides exhibit an antimicrobial activity through characteristic action mechanisms which are distinctly different from those of conventional antibiotics suffering from problems of microbial resistance, and are therefore advantageous in terms of the low risk of a microbial drug resistance. For this reason, the antimicrobial peptides have a potential of high industrial applicability in fields of pharmaceutical and food industry as they may be used as promising next-generation antibiotic substances.
However, there is a great obstacle to industrial applications of antimicrobial peptides, since conventional peptide production techniques do not permit industrial-scale production of the desired peptides at low production costs. For example, production of antimicrobial peptides by chemical synthesis is economically inefficient. Genetic engineering techniques employing microorganisms allow production of antimicrobial peptides in an economical manner, but suffer from shortcomings associated with high susceptibility of the produced peptides to breakage by the attack of a variety of microbial host proteases because most of the antimicrobial peptides are short peptides consisting of only 10 to 40 amino acid residues. Additionally, antimicrobial activity of  the expressed antimicrobial peptides suppresses growth of host microorganisms, which disadvantageously results in a very low production yield of desired peptides.
Requirements for mass expression and production of antimicrobial peptides in microorganisms are as follows. First, it is important to ensure that antimicrobial peptides are not readily decomposed by the attack of host microorganism proteases. Second, it is necessary to effectively neutralize toxicity of antimicrobial peptides on microorganisms. Conventional methods have been usually conducted using a fusion protein to produce a desired peptide from host microorganisms without causing death of host cells. However, this method disadvantageously requires separation of a desired antimicrobial peptide from the fusion protein using protease (such as Factor Xa or enterokinase) or a chemical agent (such as cyanogen bromide (CNBr) or hydroxylamine). That is, separation of the desired peptide from the fusion protein is a time-consuming and energy-intensive process, which leads to a significant decrease in the expression yield of peptide as well as a fatal disadvantage associated with unwanted residues remaining between the fusion protein and the antimicrobial peptide even after separation of the desired peptide is complete.